The SO2 sensor adopts imported sensor chip, which is used to detect the concentration of SO2 in various environments. It has the characteristics of high precision and good stability. Range: 0 ~ 100ppm resolution: 1ppm power supply mode: DC12V / 24V wiring mode: voltage type: 3-wire, current type: 3-wire, RS-485 signal: 4-wire signal output: voltage type: 0 ~ 5V DC, current type: 4 ~ 20 mA RS-485 signal: support Modbus Protocol (baud rate 9600 can be set, address 0-255 can be set) response time: < 20s, Measurement stability time: 30s sensor type: electrochemical working mode: continuous working temperature range: - 20 ℃ ~ 50 ℃ humidity range: 15% ~ 95% (RH) non condensing overall dimension: 144MM × 190mm × 74mm weight: about 1130g